The present invention, in some embodiments thereof, relates to a device and method for physical conditioning and, more particularly, but not exclusively, to a device and method for physical conditioning by lifting weights.
There are known in the art various weight-lifting machines, wherein a user exerts force on a lever in order to raise a selected number of weights from a stack of weights. U.S. Pat. No. 3,734,495 to Nist et al. discloses a weight training device for exercising the lower limbs, wherein a user's legs exert force on a lever, the lever connected via a cable or chain to a pull bar extending through apertures in a weight stack, in order to raise a selected number of weights from the weight stack. A number of weights to be lifted are selected by inserting a selector pin in an aperture in the weights and in the pull bar. The upper end of the lever is moved “by corresponding movement of the lower end of the lever in the opposite direction,” by pushing against the foot pedals, thereby raising the selected number of weights from the stack.
U.S. Pat. No. 3,905,599 to Mazman discloses a weight training device for exercising the arms, wherein a user's arms exert force on a lever, the lever connected via a cable to a weight lift rod extending through apertures in a weight stack, in order to raise a selected number of weights from the stack. The user may select a number of weights to be raised by inserting a selector pin below a stack of weights to be lifted and into an aperture in the weight lift rod. A user may raise a selected number of weights from the stack by exerting an upward force with his arms on handle bars extending from the lever. The device includes a roller on the upper end of the lift rod, such that, “as the lever arm is raised, the roller on the lift rod moves on the lever arm to reduce the user's mechanical advantage and increase his effective load.”
U.S. Pat. No. 4,546,971 to Raasoch discloses a weight lifting machine having first and second weight stacks and an assembly of levers and linkages designed to respond to force applied by a user lifting a selected number of weights from the first weight stack. The machine is also provided with a pneumatic cylinder and related linkages which lift a selected number of weights from the second stack, at a selected point in the exercise stroke, without additional force exerted by the user, thereby adding the selected number of weights from the second stack to the selected weights of the first stack.
Additional background art includes various weight lifting machines disclosed in U.S. Pat. No. 4,358,107 to Nissen; U.S. Pat. No. 4,623,144 to Rockwell; U.S. Pat. No. 4,763,897 to Yakata; U.S. Pat. No. 4,842,271 to Vinciguerra; U.S. Pat. No. 4,986,538 to Ish, III; U.S. Pat. Nos. 5,085,430 and 5,417,633 to Habing; U.S. Pat. No. 5,800,321 to Weber; U.S. Pat. Nos. 5,692,997; 5,938,575; 6,491,608; and 7,169,097 and U.S. Patent Application Publication 2004/0229737 to Stearns.